Electromagnetically operated switch



Max-ch 1944.

J. EATQN ELEGTROMAGNETICALLY OPERATED SWITCH Filed July 20, 1942 Invent-or:

dohn Eater? His Attor-he g.

, armature.

Patented Mar. 21, 1944 ELECTROMAGNETICALLY OPERATED SWITCH John Eaton, Schenectady, N. Y., assignor; to General Electric Company, a corporation oi New York 1 I Application July 20, 1942, Serial No. 451,522

8 Claims.

a strap of magnetic material having two core legs extending upward from one side with the upper end portions of the legs .bent over..in substantially parallel relation with the base, one of these pole portions being nearer the base than the other. I also provide a third core leg intermediate the other two on which is mounted a coil and on the end of which is' pivotally mounted an armature whose ends in attracted positions engage the outer side of the pole portion nearer the base and the inner side of the pole portion farther i'rom the base.

I also provide plates of electrically insulating material which are secured to the two outer core legs and which form supports for electric terminals leading to the coil, as well as supports for the contact arm and contacts actuated by the For 'a more complete understanding of my invention, reference should be had to the accompanying drawing Fig. l oi which is a plan view of an electromagneticlly operated switch embodyiny my invention Fig. 2 is a side elevation view oi the device shown in Fig. 1; Fig. 3 is an elevation view looking downward on Fig. 1; Fig. 4 is a view in perspective of the pivoted armature; Fig. 5 is a sectional view taken along the line 5-5 of Fig. 4 looking in the direction of the arrows and showing the armature in its attracted po- I sition; Fig. 6 is a perspective view to a reduced scale showing the magnetic supporting base and three core legs; Fig. 7 is a view in perspective or a small electrically conducting part for supporting the contact armsand the stationary contacts; while Fig. 8 is an end elevation view of an electrically insulating support. 7

Referring to the drawing, I have shown my invention in one form as embodied in an electric .relay. It is provided with a base member I.

(Fig. 6)' in the for-moi a strap or strip of unlaminated magnetic material such as iron, having sufllcient cross section to carry the desired amount of magnetic flux." On opposite ends of the base ID are the core legs H and I! which areintegral with the base and bent upward in parallel relation with each other and at right'angles with the base, as shown in Fig. 6. On their ends these core legs have transversely extending por- I pole portions It and I4.

tions II and It provided respectively with outer and inner pole faces.

Midway between the core legs H and I2 is a middle core leg I! which is cylindrical and has its lower end secured to the .base ID. This leg also extends in substantially parallel relation with the legs ii and II. An exciting or operating coil l6 surrounds this-middle leg and is held against the base It. Also, the fiat armature I1 is pivotally mounted on the end of this central core leg I! so that a laterally ofiset end Ila on the armature projects under the pole portion it while the opposite end ill) of the armature is directly above the pole portion 13. Thus, when the coil I6 is energized, the armature is rotated through a small angle on the central leg l5 as a pivot by reason of the attraction or the transverse pole pieces for the opposite ends of the armature. The armature comes to rest with opposite sides of its two ends engaging pole faces onopposite lower and upper sides of the For the purpose oi holding the armature in a central position on the end of the pole leg li, a yoke member II is provided having an aperture Ila (Fig. 5) in itsbase through which extends the smaller upper end 0! the leg IS, the yoke II resting and being swiveled on a shoulder ll (Fig. 6) formed on the leg I! at the junction of the smaller upper end. Secured to opposite sides of the armature l! are central laterally extending positioning trunnions 20 and H which respectively flt in slots Ila and 21a in the yoke ll provided for these trunnions. The slots are substantially parallel with the central core leg II. The engagement of the trunnions with the side walls of the slots and with the sides of the yoke definitely positions the armature centrally on the end of the core leg l5 while providing for amount'ot transverse pivotal movement of the yoke on the core leg ior adjustment purposes or for equalization purposes to prevent binding of the parts.

A spring retaining plate or clip 22 is provided to hold the yoke ll in position. This clip extends between the upstanding arms of the yoke and bears upon its base, as seen in Figs. 2 and 5. It has an elongated aperture 220. through which the end of the core leg I5 extends. One

end, as seen in Figs. 1 and 2, projects underneath the pole portion l3 and is held depressed by the pole portion. The opposite end or upper end, as seen in Figs. 1 and 2. is provided with a narrow portion 23 which projects through an aperture provided for it in a supporting end plate 24 made of suitable electrically insulating material such as a fibre or a molded compound.

This support 24 is secured to the core leg l2 by means of lugs 25 and 25 on the outer edge of the pole leg. These lugs extend through apertures provided for them in the support 24 and pins 21 and 23 extending through apertures in the lugs. These pins are furthermore wedge shaped, i. e. one end is smaller than the other, so that when they are driven into the holes in the lugs they force the support 24 tightly against the outer end or edge of the pole leg i2. A similar electrically insulating plate support 29 is secured to the other core leg I I in the same manner as the support 24 by means of lugs 30 and 3i on the leg II and wedge pins 32 and 33 extending through the lugs.

To provide for a pivotal mounting of the armature, the upper end of the central core leg l which, as shown, is a solid unlaminated rod of magnetic material provided with a plane surface parallel with the base it. Also, the armature II is actually, as shown, made of two unlaminated plates or layers 34 and 35. The plate 35 is provided with an aperture 36 (Fig. 5) through which the upper end of the leg I5 extends into engagement with the inner surface of the outer or upper plate 34. In order to provide a knife-edge pivot bearing extending transversely of the armature about which the armature is balanced, a semi-circular portion 31 on the metal of the plate 34 forming a supporting portion is stuck outward pivotally about its diameter. This portion 31 has a radius somewhat larger than the radius of the leg I5 so that when the armature moves to its unattracted position shown in Fig. 2, the semi-circular wedge shaped space or recess provided by the pressed out portion 3'! encloses one half of the upper end of the pole leg. It will thus be seen that the diametric Junction line between the portion 31 and the plate 34 forms a knife-edge bearing 33 (Fig. 5) which rests on the upper end of the leg I! and extends diametrically thereof. This bearing 33 is, of course, free to shift angularly in the plane of the upper end of the leg to take care of such adjustment as may be necessary for the assembly of the parts together. Moreover the armature is statically balanced about the bearing 35 so that the armature is substantially unaffected by shocks such as may be applied to the support on which the device is mounted.

Also mounted on opposite sides and ends of the armature II are outer and inner transverse bars 33 and 40 made of electrically insulating material such as fibre or a molded compound, these bars being secured to the armature by suitable rivets 33' and 45' which hold the plates of the armature together as well. Each of these bars operates a spring contact arm at each end. Thus. the outer bar 33 operates the contact arms 42 and 43 while the bar 40 operates the arm 44, shown in Fig. 2, and another similar contact arm (not shown) similarly mounted at the opposite end of the bar 40. Each contact arm is operatively connected to a cross bar by means of a slot 45 in the contact arm through which extends a T-shaped member 45 transversely with respect to the slot. The outer cross member on the T member 45 is shorter than the length of the slot 45 so that by turning the two parts at right angles to the positions shown in Fig. 1 the T part can be inserted through the slot. This connection has the advantage that it provides for limited longitudinal freedom of movement between the cross bar and each contact arm during the opening and closing movement.

On their movable or upper ends, as seen in Figs. 1 and 2, the arms 42 and 43 carry electric contacts 41 and 48, while their opposite ends are secured to the support 29. As shown, the arm 43 is secured to the support by providing an end portion 49 of reduced width leaving shoulders at its junction with the main portion, which end portion is slipped sidewise into a slot 50 in the support 23. This slot 50 joins with a rectangular hole 5| (Fig. 8) through which extends a relatively stiff supporting member 52 shown in Fig. 7.

In the assembly of the spring arm 43 and supporting member 52, and also other similar parts. the spring arm 43 and the member 52 are first preformed by bending their ends toward the left, as viewed in Fig. 2. The member 52 is assembled first on the insulating support 23, the elongated bent shank portion being inserted through the hole 5i and the projections 53 engaging the inner side of the support 29. Preferably, the laterally bent portion of the member 52 is then compressed firmly on the support 23 so that the support is clamped between this laterally extending end and the projections 53. To facilitate the bending of the member 52, a small aperture'54 is provided in it at the bend. Next the preformed switch arm 43 is slipped sidewise through the slot 50 to a position under the mem ber 52. Electrical connections are made to the contact arm 43 by soldering the connection to the ends of the parts 52 and 43, this connection being facilitated by providing aligned notches 55 in these parts. Moreover, the end of the spring arm is thus secured by the soldering operation to the member 52 whereby the spring arm is held securely in place.

The contact arm 42 is similarly secured to the support 23 at the same distance from the base l4 asthe arm43inthesamemannerasthearm 43 is secured to the support. Also, the contact arm44hasitsendsecuredinthismannertothc support 24 but considerably nearer the base I. so that this contact arm is engaged by the righthand side of the cross bar 45, as seen in Fig. 2. The contact arm corresponding to the arm 44 is likewise secured in this way to the support 24.

The supporting members 52 are also utilized as supports for the stationary contacts. Thus, the stationary contact 54 (Fig. 2) with which the contact 42 cooperates is mounted on a member 51 having the same construction as the member 52 of Fig. 7. In this case, a rectangular hole only without a slot is provided in the support 24 through which the preformed member 51 is inserted and secured to the support 24. This same supporting construction is utilized for the contact supports 53 and 53 as shown in the drawing. The spring contact arms are shaped so as to bias their movable contacts to open circuit positions and bias the armature to its unattracted position as shown in Fig. 2.

Preferably the contact arms and stationary contacts are assembled to the support 24 and 24 before the supports are assembled in the core legs II and [2.

A spring member 50 is provided to bias the armature toward the end of the leg i5, the lower end as seen in Fig. 2, of this member being bent to the right and engaging the armature substan: tially at its pivot center and applying a force to it. The other end of the member 50 extends curely in place.

The end of the armature which is adjacent the longer core leg I2, 1. e., the upper end as seen in Figs. 1 and 2, is laterally ofiset away from the leg I2 thereby to provide a magnetic flux insulating air gap between the side edge of the armature and the core leg l2. This effectively prevents any appreciable leakage flux from passing directly from the core leg I! to the adjacent edge of the armature and thereby prevents any consequent lateral force applied to the armature by magnetic attraction ,for the core leg II.

The insulating supports 24 and 29 likewise support the electric terminals 64 and 65 of coil it, these terminals extending through suitable apertures provided for them in the supports.

Lugs 66 and 61 are provided on the base for securing the base to a support, on which the relay is mounted.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by letters Patent of the United States is:

1. An electromagnetic device comprising an elongated member of magnetic material forming a base, long and short core legs secured to one side of said base, a transverse pole portion on the end of each of said core legs extending substantially parallel with said base and transversely with respect thereto, said .pole portions being spaced different distances from said base, a middle core leg between said first two core legs, an armature member pivotally mounted on said middle core leg and pivotally movable to an attracted position in which opposite sides of said armature engage inner and outer sides or said pole portions on said short and long legs respectively, said armature having a portion on its end adjacent said long core leg laterally ofiset away from said long core leg to provide a magnetic flux insulating air gap between said armature and said long core leg, and a winding on said middle leg for moving said armature when energized to said attracted position.

2. An electromagnetic switch comprising an unlaminated base member made of magnetic material having two core legs bent upward from one side of said base in substantially parallel relation with each other, each of said core legs having its end bent over in parallel transverse relation with respect to said base to form two D le members, a pair of lugs projecting from the outer edge of each of said core legs, a plate of electrically insulating material on the outer edge of each of said core legs provided with apertures through which said lugs extend, said lugs being provided each with a transverse aperture, tapered pins extending through said apertures on the outer side of each of said plates thereby to clamp said plates against said core legs, electric switching means carried by said plates, a middle core leg between said first two core legs secured to said base, an operating coil mounted on said middle core leg, and an armature pivotally mounted on the end of said middle core leg having its ends movable into engagement with said pole pieces when said coil is energized, and an operating connection between said armature and said switchin: means.

3. An electromagnetic device comprising a magnetic core provided with at least three sub stantially parallel core legs each having one end connected to a cross core member, a transversely extending plane surface on the other end of said middle core leg, a platelike armature mounted on the end of said middle core leg, said armature having a recess terminating in a line extending transversely of said armature to form a knifeedge bearing engaging said plane surface about which bearing said armature is balanced, and an operating coil on said middle core leg for moving said armature pivotally to an attracted position.

4. An electromagnetic device comprising a magnetic core provided with at least three substantially parallel core legs each having one end connected to a cross core member, said middle core leg having a smaller cylindrical portion on its end providing a shoulder, a yoke provided with an aperture for said smaller end mounted on said shoulder with outwardly extending arms provided with slots, 9. platelike armature extending between said arms, trunnions on opposite sides of said armature lying in said slots whereby said armature is swiveled on the upper end of said middle core leg, and an operating coil on said middle core leg for moving said armature pivotally to an attracted position.

5. An electromagnetic device comprising a magnetic core provided with at least three substantially parallel core legs each having one end connected to a cross core member, a transversely extending plane surface on the other end of said middle core leg and said middle core leg having a smaller cylindrical portion on said end providing a shoulder, a yoke provided with an aperture for said smaller end mounted on said shoulder with outwardly extending arms provided with slots, a platelike armature extending between said arms, trunnions on opposite sides of said armature lying in said slots whereby said armature is swiveled on the upper end of said middle core leg,= said armature having a semi-circular recess whose diameter extends along the transverse center of mass of said armature and forms a knife-edge bearing resting on said plane surface, and an operating coil on said middle core leg for moving said armature pivotally to an attracted position.

6. In an electromagnet, a core leg provided with a transversely extending plane bearing surface on one end, an armature having a plate-like supporting portion mounted on said bearing surface, said supporting portion having a recess terminating in a line extending transversely with relation to said bearing surface to form a knife-edge bearing engaging said bearin surface on which said armature is pivotally movable, said recess forming a space into which said end of said core leg extends during pivotal movement of said armature.

7. In an electromagnet, a core leg having a smaller cylindrical portion at one end providing a shoulder, said end being provided with a transversely extending plane bearing surface, a yoke provided with an aperture for said smaller end mounted on said shoulder, and said yoke being provided with outwardly extending arms provided with openings, a plate-like armature extending between said arms, trunnions on opposite sides of said armature extending into said openings whereby said armature is swiveled on said plane bearing surface, said armature having a. recess terminating in a line extending transversely with relation to said bearing surface to form a knifeedge bearing engaging said bearing suriace on which said armature is pivotally movable.

8. An electromagnetic switch comprising an unlaminated base member made of magnetic material having two core legs bent upward in substantially parallel relation with each other, each oi said core legs having its upper end bent over in parallel transverse relation with said base to form two pole members spaced diflerent distances from said base, a pair oi lugs projecting from the outer edge oi each of said core legs, a plate 0! electrically insulating material on the outer edge of each of said core legs secured to said lugs, said plates being provided with slots positioned opposite each other in a direction substantially parallel with the,

plane of said core legs, a spring contact arm having one end secured in one of said slots and extending to a point adjacent the second of said insulating plates, a contact supporting member secured in the second of said slots provided with JOHN EATON. 

